Abstract

Background People with germline mutation in one of the DNA mismatch repair (MMR) genes have increased colorectal cancer risk. For these high-risk people, study findings of the relationship between alcohol consumption and colorectal cancer risk have been inconclusive.
Methods 1,925 MMR gene mutations carriers recruited into the Colon Cancer Family Registry who had completed a questionnaire on lifestyle factors were included. Weighted Cox proportional hazard regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between alcohol consumption and colorectal cancer.
Results Colorectal cancer was diagnosed in 769 carriers (40%) at a mean (standard deviation) age of 42.6 (10.3) years. Compared with abstention, ethanol consumption from any alcoholic beverage up to 14 grams/day and >28 grams/day were associated with increased colorectal cancer risk (HR, 1.50; 95%CI, 1.09-2.07 and 1.69; 95%CI, 1.07-2.65 respectively; P-trend=0.05), and colon cancer risk (HR, 1.78; 95%CI, 1.27-2.49 and 1.94; 95%CI, 1.19-3.18 respectively; P-trend=0.02). However, there was no clear evidence for an association with rectal cancer risk. Also, there was no evidence for associations between consumption of individual alcoholic beverage types (beer, wine, spirits) and colorectal, colon, or rectal cancer risk.
Conclusion Our data suggests that alcohol consumption, particularly more than 28 grams/day of ethanol (~2 standard drinks of alcohol in the US), is associated with increased colorectal cancer risk for MMR gene mutation carriers.
Impact There was only limited evidence that alcohol consumption in MMR gene mutation carriers is associated with colorectal cancer risk.